You have fought a pitched space battle against high-resolution enemy starships, watched your 3D troops and armored vehicles pound the enemy to pieces, then the planetary display screen shows destroyed improvements marked out with an "X"?!?!?!?! To promote a collective move away from interstellar tic-tac-toe, here is a little mushroom cloud icon to substitute for the Big Red X.

NOTE: The thumbnails are out-of-date; the area around smoke ring at the base of the cloud is no longer illuminated.